This invention relates generally to bedding mattresses, and more specifically to mattresses having an improved border support.
Typically, a mattress comprises a spring core or so-called spring assembly covered on the top and bottom sides by fabric or cushioning pad and encased with an upholstery covering. The spring core generally comprises rows of coil springs laced together in the top and bottom planes of the springs and surrounded by top and bottom border wires. Additionally, the mattress may have border support springs mounted between the top and bottom border wires to provide additional stiffness or support around the outer border of the mattress.
In normal use the mattress and coil springs are subjected to increased local loading along the borders of the mattress which tends to diminish not only the appearance of the mattress but also the comfort it may provide. For example, sitting on the edge of the bed will depress the top border wire to the point, in time, where it may acquire a permanent deformation. Furthermore, this can result in an uncomfortable tilting or sloping of the bed to one side resulting in a tendency for one to roll to the low side of the bed. The present invention is directed to an improved mattress having resilient support in the form of border support springs around the outer border of the mattress to alleviate these problems.
Even though border reinforcing springs have been developed in various forms, a common problem with these configurations is that the spring structure can be relatively "loose" so that movement of the spring can result in undesirable noise. The noise which results from the use of known border reinforcing springs is a result of the fact that the torsional members which provide the resilient support are not secured tightly together along their entire length. This enables the torsion members to slip relative to one another during use thereby generating the undesirable noise associated with known border reinforcing springs.
Another problem with many forms of border support springs is that they are not sufficiently designed to provide a resilient support structure initially and throughout the life of the mattress. Commonly, border support springs wear out or become ineffective prior to the end of the useful life of the mattress itself. The reason that past border support springs wear out and become ineffective, or are even insufficiently resilient when made, is that the torsion members which are used to construct the spring are only of limited length. Known border springs are constructed by twisting or interlocking a portion of the torsion elements together. This twisted portion does not offer resilient support between the top and bottom border wires. Only the non-twisted length of torsion wire is effectively resilient. Furthermore, these less resilient border springs currently in use are not well suited for mattresses having a large gap between the top and bottom border wires or high profile mattresses. These high profile mattresses are currently inadequately supported around the edges due to the limited resiliency offered by the shorter torsion lengths of known border springs.
The nature of mattress manufacturing is that mattress spring cores, or so-called spring assemblies are generally manufactured in one facility and then shipped to a second facility where the cores are covered and upholstered. In the course of upholstering the spring core of the mattress at the second facility, accessories such as border support springs may be added to a standard core so as to differentiate mattress models or styles. Mattress upholsterers customarily do not have the equipment or the capabilities of the mattress manufacturer; therefore, the assembly and installation of the border support springs must be easily achieved with a minimal amount of effort, expertise, or equipment.
Border support springs currently used in the industry are not easily manipulated for assembly into a manufactured mattress in that they are of fixed construction. The center section of the border support spring must be positioned behind the outer most coil springs with the border spring arms projecting between adjacent coil springs to be attached to the top and bottom border wires. To incorporate the border spring into an assembled coil spring mattress, one end of the border spring having two border spring arms must be inserted between adjacent coil springs and then wrapped around and behind the outer most coil springs until the arms re-emerge at the edge of the mattress to be attached to the top and bottom border wires respectively. The installation of known border support springs into the mattress is very difficult because the arms are fixed in a spaced relationship rendering the "fishing" of the spaced arms into, around, behind, and out of the coil springs very time consuming and labor intensive. Furthermore, the mattress manufacturing industry is highly competitive and the manufacturing costs associated with a given mattress often differentiate between a commercially successful mattress and others.